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[Runtime
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](../../guides/index.md)[Reference
](https://bun.com/reference)[Blog
](https://bun.com/blog)[Feedback
](../../feedback/index.md)
Bun itself is MIT-licensed.
[
](#javascriptcore)
JavaScriptCore
Bun statically links JavaScriptCore (and WebKit) which is LGPL-2 licensed. WebCore files from WebKit are also licensed under LGPL2. Per LGPL2:
(1) If you statically link against an LGPL’d library, you must also provide your application in an object (not necessarily source) format, so that a user has the opportunity to modify the library and relink the application.
You can find the patched version of WebKit used by Bun here: https://github.com/oven-sh/webkit. If you would like to relink Bun with changes:
git submodule update --init --recursivemake jsczig build
This compiles JavaScriptCore, compiles Bun’s .cpp bindings for JavaScriptCore (which are the object files using JavaScriptCore) and outputs a new bun binary with your changes.
[
](#linked-libraries)
Linked libraries
Bun statically links these libraries:
Library
License
MIT
BSD 3-Clause
MIT
dual-licensed under the Perl License or the MIT License
dual-licensed under the BSD License or GPLv2 license
Apache 2.0
LGPL v2.1
Apache 2.0
zlib
MIT licensed
libicu 72
BSD 2-Clause
libuv (on Windows)
MIT
MIT
A fork of uWebsockets
Apache 2.0 licensed
Parts of Tigerbeetle’s IO code
Apache 2.0 licensed
[
](#polyfills)
Polyfills
For compatibility reasons, the following packages are embedded into Bun’s binary and injected if imported.
Package
License
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
MIT
[
](#additional-credits)
Additional credits
- Bun’s JS transpiler, CSS lexer, and Node.js module resolver source code is a Zig port of @evanw’s esbuild project.
- Credit to @kipply for the name “Bun”!
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